以宏基因组技术探讨渤海秋冬季节病毒多样性

为研究渤海海域病毒群落总体状况,本文以渤海的B47站表层海水为代表,对两个时间点(2010年9月,2011年12月)的病毒宏基因组做出全面分析。采集海水样品后过滤并经过切相流系统浓缩,提取DNA测序,再进行生物信息学分析,包括病毒组的种群分类、功能基因分析、系统进化分析等。分析结果指明,这两个时间点的病毒群落均由双链DNA病毒(97.75%,scaffold百分比)占据优势地位,其中尤以有尾噬菌体(80.86%,scaffold百分比)居多。按宿主区分,最大的一类病毒为聚球藻噬藻体(10.29%,scaffold百分比)。渤海病毒群落最为丰富的功能基因为复制、结合和修复基因,且冬季(33.77%,ORF百分比)大于秋季(16.39%,ORF百分比)。结果表明:在渤海病毒组中,(1)存在理论上只出现在亚热带海域的原绿球藻噬藻体;(2)物种组成、物种多样性、功能基因比例呈现季节变化;(3)相比远洋病毒组有一定独特性;(4)可能存在未知的T4-like病毒分支。

METAGENOMIC STUDY ON VIRAL DIVERSITY IN AUTUMN AND WINTER IN BOHAI SEA

To study the viral community, we collected two surface water samples in September, 2010 and December, 2011in Bohai Sea, China. Virome study included taxonomic analysis, functional gene analysis, and phylogenetic analysis. Samples were filtered and concentrated by TFF (Tangential Flow Filtration) for DNA extraction. Results show that dsDNA virus (97.75%, scaffold percentage), especially the most abundant order Caudovirales (80.86%, scaffold percentage), was dominant in both samples. Classified in the host, Synechococcus phage (10.29%, scaffold percentage) was the main component. Furthermore, the most common functional genes of virioplankton in Bohai Sea were those for replication, recombination, and repair, and the proportion in winter (33.77%, ORF percentage) was more than that in autumn (16.39%, ORF percentage). Moreover, phylogenetic analysis indicated that the viral genes are clustered with conserved domains of Synechococcus phage, Pelagibacter phage, and Prochlorococcus phage. The virome included few Prochlorococcus that existed theoretically in subtropical waters. The species diversity and functional gene proportion varied seasonally in own unique characteristics to that of pelagic ones, and a possible branch of unknown T4-like phage may exist.